Tropical fruits are most afraid of freezing
Most tropical fruits are afraid of cold, so they are not suitable for cold room for fruits. Frostbitten fruit is not only damaged in nutrients but also easily deteriorated. In a few days, the flesh will rot. Usually, the pitaya, mango, litchi, longan, papaya, rambutan, etc. are put into the refrigerator once they are bought home. Within a few days, the skin of the fruit begins to sag, showing dark brown spots, which indicates that the fruit has been frostbitten. Banana and mango will turn black when they are kept at 10 ℃; pineapple will turn black when they are kept at 6 ℃ - 10 ℃; litchi, longan, and rambutan will turn black when they are kept at 1 ℃ - 2 ℃, the color of the outer peel will turn dark, and the inner peel will appear spots like scald, which can't be eaten anymore.
Storage method: tropical fruits are best stored in a dark and cool place. If it is necessary to put it into the refrigerator, it should be placed in the vegetable and fruit trough with a higher temperature, and the storage time should not exceed two days.
Temperate fruits like cold temperature
Generally speaking, temperate fruits, such as grapes, apples, pears, etc., can be kept fresh in the refrigerator.
Storage method: put vegetables and fruits in plastic bags
People usually put the bought fruits into plastic bags and then store them in cold room for fruits. The principle is to reduce the concentration of low oxygen, increase the concentration of carbon dioxide, make the fruits and vegetables in a dormant state and extend the storage period. However, the storage time should not be too long. Because vegetables and fruits are organic food, they contain high water content (60% - 95%), and water-soluble nutrients and enzymes. During the whole storage period, there was still a strong respiratory activity. In general, every 10 degrees Celsius rise, the respiratory intensity will double. Under the aerobic condition, the sugars or other organic substances in fruits and vegetables will oxidize and decompose, producing carbon dioxide and water, and releasing a large amount of heat. Under the anoxic condition, the sugars cannot be oxidized, only can decompose to produce alcohol, carbon dioxide, and a small amount of heat. However, the concentration of carbon dioxide cannot be increased indefinitely, only 10%. The decrease in oxygen concentration should not be more than 5%. Otherwise, to obtain enough energy for life activities, fruits and vegetables must decompose more nutrients. At the same time, the alcohol produced by the oxygen-deficient respiration will be left in the fruits and vegetables, which will cause the fruits and vegetables to rot, so the storage time of the fruits and vegetables in the plastic bag should not be too long. If you want to store fruits and vegetables in a plastic bag, please don't be afraid of trouble. Open the mouth of the plastic bag every two or three days, release carbon dioxide and heat, and then tie the mouth up, to reduce the occurrence of decay.